Understanding the resilience of Amazon floodplain forests

  • Contact:

  • Project Group:

    Florian Wittmann (Karlsruhe Institute for Technology, Germany), Bernardo Flores (Universidade Estadual de Campinas, Brazil), Milena Holmgren (Wageningen University, the Netherlands), Jansen Zuanon (Instituto Nacional de Pesquisas da Amazônia, Brazil), and Arnold Lugo (Instituto Nacional de Pesquisas da Amazônia, Brazil).

  • Funding:

    European Commission Individual Fellowship (grant no: 746181)

  • Startdate: 08/2017
  • Enddate: 07/2019
Climate models consistently predicted an intensification of ENSO droughts and associated forest fires in most of the Amazon basin. Amazonian floodplain forests, although submerged during the wet season, are highly susceptible to burn during drought years. After burning, they poorly regenerate, and with repeated fires can transition to a savanna-like state in which the forest appears unable to regenerate altogether (Flores et al. 2016, 2017). Why this collapse occurs is unknown. Previous research suggests that seed dispersal limitations may play a fundamental role in understanding the resilience of floodplain forests to fire perturbations. Fire destroys the seed bank completely, and the input of new tree seeds during the high-water season might be a crucial bottleneck for the regeneration of floodplain forests. In particular, the ability of tree seeds to reach ‘collapsed’ floodplain areas might depend on whether or not fish still exploit these areas. Amazonian fishes heavily consume fruits and seeds during the flood season and may play a pivotal role in the successful dispersal of floodplain trees. As Amazonian fishes depend almost exclusively on the floodplain forests for food, the collapse of these forests will have dramatic consequences for fish communities, possibly creating a feedback loop that contributes to the sparse tree-cover state of burned floodplains. In this research project, we are investigating the ecological barriers that explain arrested regeneration of Amazonian floodplain forests after recurrent fire by evaluating the pathways of seed dispersal and the effects of fire on the composition and abundance of fish and tree communities.